Description
In the Linux kernel, the following vulnerability has been resolved: net/sched: hhf: cap hh_flows_limit at change time hhf_change() stores TCA_HHF_HH_FLOWS_LIMIT with no upper bound. A huge hh_flows_limit lets each new heavy-hitter flow pass the hh_flows_current_cnt check in alloc_new_hh() and forces a fixed-size kzalloc(GFP_ATOMIC) per flow under spoofed traffic, for unbounded memory growth. Bound the attribute with NLA_POLICY_MAX() at 2*HH_FLOWS_CNT (the hhf_init() default) and report the rejected value via extack. The deprecated nested parse is kept: legacy tc does not set NLA_F_NESTED on TCA_OPTIONS. Configs relying on hh_limit above the default were relying on unbounded, unsafe behaviour and are not supported going forward. hhf_init() also ran hhf_change() before setting the default hh_flows_limit, so a user-supplied hh_limit at add time was clobbered back to 2048. Set the default before hhf_change() so the configured value sticks. This is a follow-up to commit eb56a495f59b ("net/sched: hhf: clamp quantum in change and init paths"), which bounded the quantum of the same qdisc; the hh_flows_limit bound is the remaining unbounded knob of that series' scope. Conditions to recreate the bug: CAP_NET_ADMIN in a user namespace; tc qdisc change dev X root hhf hh_limit 4294967295 succeeds and the value is echoed by tc qdisc show, unbounding heavy-hitter flow allocations; also tc qdisc add dev X root hhf hh_limit 500 stores 2048 instead of 500.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
10239edf86f137ce4c39b62ea9575e8053c549a0 to < 7adfd0a42174b85c6bd678858ecd6674f403f336affected10239edf86f137ce4c39b62ea9575e8053c549a0 to < 35fd423a5c5132c6f4321f6c4f0a7b4b90af830caffected10239edf86f137ce4c39b62ea9575e8053c549a0 to < 06d2a101e89063cb0b9b459104db48bdfb0a797daffected10239edf86f137ce4c39b62ea9575e8053c549a0 to < d8e2f1f0263b7c97b222c06070cccf13e0ab7112affected10239edf86f137ce4c39b62ea9575e8053c549a0 to < f3f4a5cb4a6e9b1f1f25d34dfc25f836a1601db4affected10239edf86f137ce4c39b62ea9575e8053c549a0 to < 1731ff1d20489afe4cd01b7d16d37f324746ac54affected10239edf86f137ce4c39b62ea9575e8053c549a0 to < f6547d27ce2093c5627636fb63dd0b7523c466f9affected10239edf86f137ce4c39b62ea9575e8053c549a0 to < 2cef2588c995722a901368def30befeef9ae55c6affected
Linux Linux
Default version status: affected
3.14affected0 to < 3.14unaffected5.10.271 to ≤ 5.10.*unaffected5.15.222 to ≤ 5.15.*unaffected6.1.189 to ≤ 6.1.*unaffected6.6.158 to ≤ 6.6.*unaffected6.12.112 to ≤ 6.12.*unaffected6.18.54 to ≤ 6.18.*unaffected7.2.8 to ≤ 7.2.*unaffected7.3 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/7adfd0a42174b85c6bd678858ecd6674f403f336 ↗
- https://git.kernel.org/stable/c/35fd423a5c5132c6f4321f6c4f0a7b4b90af830c ↗
- https://git.kernel.org/stable/c/06d2a101e89063cb0b9b459104db48bdfb0a797d ↗
- https://git.kernel.org/stable/c/d8e2f1f0263b7c97b222c06070cccf13e0ab7112 ↗
- https://git.kernel.org/stable/c/f3f4a5cb4a6e9b1f1f25d34dfc25f836a1601db4 ↗
- https://git.kernel.org/stable/c/1731ff1d20489afe4cd01b7d16d37f324746ac54 ↗
- https://git.kernel.org/stable/c/f6547d27ce2093c5627636fb63dd0b7523c466f9 ↗
- https://git.kernel.org/stable/c/2cef2588c995722a901368def30befeef9ae55c6 ↗